Nucleation of polyolefins

ABSTRACT

Nucleation of polyolefins is enhanced by the presence of a polyolefin having an alkali metal sulfonate and chlorine group separately attached thereto and containing an alkali metal hydroxide, preferably sodium hydroxide dispersed in the melt prior to solidification.

United States Patent 1 Johnson et al.

Sept. 2, 1975 NUCLEATION OF POLYOLEFINS Inventors: Burnett H. Johnson; Terrence Huff, [56] References Cited both of Baytown. Tex. UNITED STATES PATENTS Assignee: Exxon Research and Engineering 3,022,276 2/1962 Orthner 260/7943 R p y Linden NJ. 3 320,2l8 5/1967 Levine 260/79.3 R

Filed! 00L 1972 Primary E.\-aminerChristopher A. Henderson Attorney. Agent. or Firm-T. B. McCulloch; David A 1. No.: 301,939

pp A. Roth Related U.S. Application Data Continuation-impart of Ser. No. l79,884 Sept. 13, 1971, abandoned.

[ 5 7] ABSTRACT Nucleation of polyolefins is enhanced by the presence of a polyolefin having an alkali metal sulfonate and chlorine group separately attached thereto and containing an alkali metal hydroxide, preferably sodium hydroxide dispersed in the melt prior to solidification.

U.S. CL... 260/79.3 R; 260/45.7 P; 260/45.7 S; 260M595; 260/93.7; 260/878 R; 260/897 C; 260/897 8; 260/DIG. 35

Int. Cl. C08f 27/07 Field of Search 26()/79.3 R, 897 B, 897 C 8 Claims, 1 Drawlng g r I? 9 2 so; [8 o 27 LAMP g cc! l4 2 28 ll l2 vAcuuM }32 23 DRIER FEED SLURRY V f I5 I6 coouuc I J FLUID HOT AOUGOUS' "00H 33 POWDER 36 WASHWATER liE l 35 A STABILI ZER 44-l 46 vacuum omen METHANOL" WATER VACUUM 57 DRIER SODIUM HYDROXIDE SOLUTION lN METHANOL'WATER PRODUCT PAIENIED E 2 I915 C22 CC14 FEED SLURRY CCQ4 LAMP 22 VACUUM DRIER COOLING FLUID HOT AQUEOUS NuOH POW DER WATER WASH WATER STABILIZER N S O R S 0 ET 9 HFW 4 m m N E18 E E: 4 T C .2 T N E E NR R R m U E B T R U UE CR AD V 2 4 4 ml 1 4 5&4 L 0 7 NR 5 5 \I\ II E \HH MT 5 M T A n EW 6 M W 5 UE CR AD V T C 8 u 5 D O R P SODIUM HYDROXIDE SOLUTION IN METHANOLWATER NUCLEATION or POLYOLEFINS I CROSS-REFERENC E TO RELATED APPLICATION This application is a continuation-in-part of Ser. No. 179.884. filed Sept. I3. I97] and now abandoned. for Burnett H. Johnson and Terrence Huff and entitled Nucleation of Polyolefins."

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to the crystallization of polyolefins. More specifically. the invention is directed to the crystallization of polyolefins wherein chlorine and alkali metal sulfonate groups are separately attached to a polyolefin and an alkali metal hydroxide. preferably sodium hydroxide. is dispersed in the melt prior to solidification.

2. The Prior Art It is known in U.S. Pat. No. 3.327.021 to 'add alkali metal salts of certain monosulfonic acids to polyolefins such as polypropylene having a crystalline structure to modify the crystallization process. Thus. sodium salts of sulfonic and aminosulfonic acids have been added to crystalline polyolefins with beneficial results. However, addition of the sodium salts requires separate manufacture of the salts and the separate addition of them and incorporation in the melted polyolefin. We have now found that advantageous results and a new product may be obtained by chlorination and sulfochlorination of crystalline polyolefin wherein chlorine and sulfonyl chloride groups are introduced into the polyolefin molecule followed by treatment to form a chlorinated and alkali metal sulfonated polymer which has beneficial and unobvious properties in that. in the presence of an included-alkali metal hydroxide phase. improved nucleation is obtained. Further. we have found that the composition may be stabilized by adding thereto in addition to the alkali metal hydroxide such as, but not limited to, sodium hydroxide a stabilizer which may be 2.6 ditertiary. 3-methyl phenol and any of several known stabilizer packages for polyolefins.

Other prior art is Kulne. C. .1. ct al.. S.P.E. Journal, October 1964. Additional art is U.S. Pat. Nos. 3.022.276 and 3.320.276.

SUMMARY OF THE INVENTION The present invention is directed to a polyolefin composition of enhanced nucleation which comprises a solid polyolefin of a mono-alpha-olefin having 3 to 8 carbon atoms having a crystalline structure and containing approximately equimolar amounts of chlorine and alkali metal sulfonate groups separately attached to a polyolefin. and having an alkali metal hydroxide, preferably sodiumvhydroxide, present in an amount effective I to improve nucleation. preferably between about 0.5 to 2.0 times the weight percentage of the metal sulfonate present in the polyolefin. having been dispersed in a melt of the polyolefin prior to solidification. The composition of the present invention may be the mixture produced by the chlorination and sulfochlorination of the polyolefin which is converted to the salt or may be a mixture of the alkali metal sulfonated and chlorinated polyolefin which is admixed with virgin crystalline polyolefin. In either case. an alkali metal hydroxide. preferably sodium hydroxide. is dispersed in the polyolefin in an amount effective to enhance nucleation.

BRIEF DESCRIPTIONOF THE DRAWING Theinvcntion will be further illustrated by reference to the drawing in which the single FIGURE is a flow diagram of a preferred mode and embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS WITH'REFERENCE TO THE DRAWING Referring now to the drawing, and particularly to the sole FIGURE. numeral 11 controlled by valve 12 designates a feed line in which a slurry of ethylenepropylene copolymer or polypropylene powder in carbon tetrachloride is fed into a reactor vessel 13 provided with a cooling jacket 14 through which cooling fluid circulates by lines 15 and 16 to maintain the temperature in the reactor vessel 13. Reactor vessel 13 is provided with line 17 controlled by valve 18 for admitting chlorine and line 19 controlled by valve 20 for admitting S0 Reactor vessel 13 is also provided with an ultra-violet light source 21 which receives electrical energy by electrical leads 22 connected to a source of electrical energy. Reactor 13 is also provided with a power driven stirring means 23. Carbon tetrachloride may be introduced into reactor vessel 13 by line 27 controlled by valve 28. After the requisite period of time with chlorine and S0 being fed into the feed slurry of crystalline polypropylene or crystalline propylene-ethylene copolymer the product is withdrawn by line 29 into a vacuum driver 30 provided with a heating means 31 and a line 32 connected to a source of vacuum not shown by way of which the product is freed of carbon tetrachloride by drying and the carbon tetrachloride is recovered for reuse.

Before this takes place, however. the feed slurry is cut out by closing valve 12 and the product in reactor vessel 13 is washed several times, say four or five times. with carbon tetrachloride introduced by line 27 and valve 28 from a source not shown.

After the vacuum-dried material has been dried in vacuum drier 30, the powder is routed by means 33 into a vessel 34 where it is treated with hot aqueous sodium hydroxide or any other alkali metal hydroxide solution introduced by line 35. After a suitable period of time and agitation with means 36 the product therefrom is removed by line 37 and water washed in means 38 with water introduced by line 39. The wash water is discharged by means not shown and then the washed product is introduced by means 40 into a second vacuum drier 41 which is similar to vacuum drier 30 and provided with a heating means 42, a line 43 for removal of waterv which is provided with a vacuum means not shown. and line 44 for removal of product. As the product is removed by line 44 stabilizer may be introduced in-a suitable solvent by line 45 controlled by valve 46 into a vacuum drier 47 which is similar to the other vacuum driers. being provided with a heating means 48, line 49 for withdrawal of solvent and for pulling vacuum on the drying system. and line 50 for withdrawal ofthe powder containing the stabilizer. The stabilized product containing the chemical stabilizer is then introduced into a treater SI provided with a mixing means 52 into which sodium hydroxidesolution in methanol and water is introduced by line 53. The contents of treater 51 are stirred by mixing means 52 for the ref qui .ed amount of time and then the product is withdrawn by line 54 into another vacuum drier 55 provided with heating means 56 and line 57 for withdrawal of methanol and'water in which the sodium hydroxide solution is dissolved. The vacuum dried and stabilized product stabilized with both the stabilizer introduced 4 stabilizers. while the impact propyleneethylene copolymer is a commercial copolymer having better than 80% hot heptane insolubles. This latter material was received as a pelletized material and ground to a fine by line 45 and the sodium hydroxide by line 53 is with- 5 powder under liquid nitrogen prior to reaction. it con drawn by line 58 for further use as desired. The product mi d b t 25 weight percent ethylene and w wbiis an improved P having improved nucleation lized, the stabilizers not being removed prior to reac- P p melting and solidification tion. The sulphur dioxide was anhydrous grade of VARIABLES OF THE INVENTION 99.98% Or better purity and W218 USCd a? I'CCCiVfid, and

- lo the chlorine was 99.5% or better purity used as re- In the reactor 13 the slurry of crystalline polypropylceived. Carbon tetrachloride and sodium hydroxide one or crystalline propylene-ethylene copolymer is ex- 0 were reagent grades and were used as received. It is unposed to ultra-violet light at a temperature of about 0 derstood that other 01 mcrs CO 01 mcrs ma be to about 70C., preferably about 3 to l0C., more prefused p y p y y erably 5 21 the 5 from about 5 7' l5 Thus, while polyolefins such as illustrated and mixabout 90 minutes. By virtue of this exposure to ultratures of polyolefins may be employed, grafted polyoleviolet light in the presence of chlorine and sulphur dif I I I ins such as acrylic acid and glycidyl acrylate grafted oxide introduced by lines 17 and 19 the slurried powl l b d h th I dered polyolefin is chlorinated and sulfochlorinated p0 yo 6 ms may 6 use 6 p0 ymcr comdmmg about 0.01% to about by wt. of the grafted compowhile agitating same with the agitating means 23. 2o nm T i i x g i T by Likewise, fillers and reinforcing agents may be used ":5 i t g lsfwds c y r such as glass fibers, talc, bentonite, clays, asbestos, and on 6 mm me f Say our f; was mgs g the like. The amount of the fillers will depend on the about two pounds 0 Carbon ten-ac 8 P P 0 degree of reinforcement needed for the particular polypolymer per wash. The washed material withdrawn mcr and wage by 29 vacuum i and carbon The chlorosulfonation of the polypropylene and the "b gf i g by Pg f d fifif f copolymer gives a product containing both 50 C] i m t 6 a mm d or groups and Cl groups. However, this product has no from out 8 to f Ours un er m pres form of stability as long as the sulfonyl chloride group sure of about 1 to 30 millimeters. The powdered sulfo- 30 is present chlorinated and chlorinated material is treated at a The molar ratio of soqNmNaoH in th: mass is within temperature from about 600 to about 100C while the range from about l.35:l to about 0.3:], and the tating from about 3 to about 8 hours in treater 34 with molar ratio of sonNazcl is within the range of from hot sodlum hydrox'de whlch may a about 2.0:l to about 0.1:]. A preferred molar ratio of strength within the range between l.l0 to 1.33 specific 35 soaNazNaoH in the mass is from about 08: to about gravity at After the Sulfochlorinatcd and chlori' 0.5:1. A preferred 'molar ratio of SO;,Na:Cl is from "f polymfir has been mated with hot aqueous about l .5:l to 2: l,'although a higher ratio may be used. l ydmxldc to convert sulfonyl groups These ratios may be provided by treating the sulfonated to sodium sulfonate groups it is then subyected to water and chlorinated polypropylene or copolymer with n Washing about 5 W Washcs Water Wash excess of NaOH after the treating and subsequent means the Watcl' g discharged y means not steps. A nuclcating amount of 0.05 to 1.02 mole pershown. Thereafter thC wet material IS sent to another can metal sulfonate groups in the polymer is de. vacuum d e Where it is dried at a temperature fmm sirable. A preferred range is from about 0.1 to 0.5 mole about 40 to 10 C. fo a time Of about 8 24 hourspercent of alkali metal sulfonate groups in the polymer. Finally the vacuum dried material may have a stabilizer In any event, the presence of a nucleating amount of added to it which may be 2. i r y. -methyl phc- NaOH as such is important in stabilizing the mass and no] in methanol or other stabilizers such as distearyl in improving the nucleation rate of the polymer on sothioldipropionate, dilauryl thiol dipropionate. tris (4- lidifying from the melt. nonyl phenyl phosphite, butyl zimate and the like. The While the foregoing ratios and amounts are given for stabilized material is then introduced into a vacuum the-sodium sulfonate groups'und NaOH, the ratios and drier where the solvent for the stabilizer is removed. mount apply e ll t th Qther Ik li w] ulfo. This solvent may suitably be a solvent as described bemites and hydroxides. fore. Thereafter the procedure is as shown in the de- In the following table the mechanical property scription taken with the drawingdata on injection specimens of sodium sulforiated The polypropylcnes employed are powders having 5 and chlorinated polypropylene=ethylene copolymerare better than 93?! hot heptane insolubles containing no shown.

TABLE I MECHANICAL PROPERTY DATA ON INJECTION MOLDED SPFIlMFiNS Polypropylene Ethylene unolynier Sample of Homo- Homo= Hoino= Honio= Honio= Lot lint l Lot 2 Lot 2 polymer polymer polymer polymer polymer l (Sm Niil (SO Nu) I +NiiOH +Na0l=l (S0,, Nil) Na) (SO Nil) NiiOH NaOH Wt.'/i S0,. Nu l 1 None 5.02 0.32 None Hi7 None (Llh None 0.6 4 Will: (I None 1.6 0.7 None 0.39 None 0.05 None 0.26 Wt.'/i NaOH None None 0.104 None [.00 None ills None 0.40

TAB LE l Continued MECHANICAL PROPERTY DATA ON INJECTION MOLDED SPECIMENS 7571 hy \vt. Propylene-257i by wt.

Polypropylene Ethylene Copolymer Sample of Homo- Homo- Homo- Homo- Homo- Lot Lot 1 Lot 2 Lot polymer polymer polymer polymer polymer I (SO Na) (80' Na") 2 +NaOH +NaOH (50 Na) (SO; Na) (S Na) NaOH NaOH MF. 0.3 o.0| (1.06 3.0 0.10 3.9 2.3 3.9 0.1 Flex. Modulus 195 168 214 200 232 137 155 143 161 11) psi) I Tensile. Yield (psi) 6067 7010 5104 60711 4084 41173 3582 4094 A Elong. Yield 25.0 42.0 14.1 28.1 12.0 16 7 8.3 17.7 Room Temp. Notched Izod (ft-lhs/in notch) 2.2 3.1 5.3 1.5 1.3 3.0 2.7 4.7 6 Unnotehed lzods at F. 5.0 11.6 7.5 9.1 7.2 NB NB 36.9 33.2 2() F. 5.1 9.5 6.7 5.7 6.1 21.2 37.2 27.9 27.1 4() F. 5.2 8.6 5.7 6 2 22.5 19 9 24.4 25.5 Cryst. 1/2 Time at 135 C. (min) 3.1 0.5 11.4 0.6 5.6 1.8 5.9 0.4 T,.("C.) 111 1 1 18 1,24 1 17 126 120 122 121 131) All run at SO- -/(1 ratio 2.5/1. Temp. C.....molar ratio SQfNalCl -(LX. I I'c (rysL Temp. from temp. Perkin Elmer DSC-1B at AT 1(1C./Min. and is related to nucleation .rate.

Homopolymers 1 and (2) are merely different EXAMPLE 1 grades of polypropylene employed in Tables 1 and 11.

The dual requirement of both alkali metal sulfonate groups on the polymer and an included alkali metal hydroxide such as sodium hydroxide phase in order to obtain a highly nucleated polymer are shown in Table 11.

Blend I 1.7 wt.7z SO Na and 1.1) wtf/Z NaOH.

Blend 11 TABLE I] 400 gms homopolypropylene powder (l)'wcre bag mixed with 100 gms of the unmodified homopolypro- Nl'CLF-IATION DATA ON SELECTED POLYPROPYLENE Py Powder used to P p Sodium Sulfomlted P y- SAMPLES propylene. s. I Fl w H wt V T2 Each powder blend was extruded (()F.), pelletso J Q- ized. and injection molded to test specimens (47()F. Properties of the two blends are shown in Table III. Homopolymer" None None I 17C.

NaOH None 0.5 116C. 40 EXAMPLE SO; Na" (1.4 None 1 17C. so Nip" 5.0 None 120C. Blend NH.N;1'()H 0.4 0.2 C. 400 gms of C /C (ethylene-propylene) copolyso N11'.N11'()H 3.0 3.0 125C. d b, d h 100 f Lu 2 NOW Nunc 120C mer pow er were ag mixe wit gms 0 1m 2, NaOH None 0.5 120C. SOfNaU copolymer powder of the present invention. Lot 2. SO Na" (1.4 None 120C. 45 l m 2 so Nay NUIOH H (H H) C This copolymer eontams 0.49 wt. SQ, Na and 0.28

wt.'/: NaOH.

Sample designation as in lahle I Blnd l. definition and igl eunee as in "'.'lz1l\le 1 Molar ratio SO Nn'll in these polymer (LN.

Sodium sulfonated polypropylenes containing an included sodium hydroxide phase are also useful as additives to unmodified resin for mechanical property improvement.

TABLE I11 400 gms homopolypropylene powder were bag mixed with 100 gms of homopolypropylenc (SOJ Na powder (sodium sulfonated polypropylene). Sodium polypropylene; prepared as described previously contains Properties of Blends Containing Polypropylene Sodium Sult'onates and Sodium Hydroxide See 'l'ahle l for description Again the improvement in both nucleation rate and mechanical properties was obtained in the blends containing the sodium sulfonated and chlorinated polypropylenes containing an included sodium hydroxide phase.

It will be seen from a comparison of the various poly.- propylene that the sodium hydroxide contributed to the improved nucleation rate and mechanical properties of both the polypropylene and the copolymer.

The present invention is quite advantageous and useful and may be used as molding grade polypropylene for making various articles.

The invention is unique and unobvious in that the sodium sulfonate and the chlorine are attached separately into the polypropylene and the sodium hydroxide functions to enhance the nucleation rate and along with the other stabilizers adds stability to the mass. We have, therefore, invented a new, unobvious and useful composition and method for producing same.

The nature and objects of the present invention having been completely described and illustrated and the best modes and embodiments contemplated set forth, what we wish to claim as new and useful and secure by letters patent is:

l. A method for preparing chlorinated and sulfonated solid polyolefin of an alpha mono-olefin having 3 to 8 carbon atoms in the molecule which comprises:

exposing a stirred slurry of solid crystalline polyolefin powder is carbon tetrachloride to a sufficient amount of S and Cl in the presence of light for a sufficient length of time at a sufficient temperature V to sulfoehlorinate and chlorinate said solid polyolefin;

drying the resultant slurry of sulfochlorinated and chlorinated polyolefin;

treating said dried sulfochlorinated and chlorinated polyolefin with a hot aqueous alkali metal hydroxide solution to convert said sulfochlorinated polyolefin to the alkali metal sulfonate form;

drying the treated chlorinated and alkali metal sulfonated polyolefin; and then stabilizing the last dried polyolefin by adding thereto at least a sufficient amount of alkali metal hydroxide;

with the proviso that the amounts of S0 C1 aqueous metal hydroxide solution and alkali metal hydroxide added thereto are sufficient to provide said polyolefin with a molar ratio of the alkali metal sulfonate group: alkali metal hydroxide within the range from about 1:35;] to about 0.3: l the molar ratio of the alkali metal sulfonate group: Cl within the range of from about 2.0:] to about 0.1:], and the alkali metal sulfonate groups constitute from about 0.05 to about 1.02 mole per cent of said polyolefin.

2. A method in accordance with claim 1 in which the alkali metal hydroxide is sodium hydroxide.

3. A method in accordance with claim 1 in which the slurry is exposed to S0 and Cl for a time within the range of about 5 to about 90 minutes at a temperature of about 0 to about C.

4. A method in accordance with claim 1 in which the dried chlorinated and sulfochlorinated polyolefin is treated at a temperature from about 60 to about 100C. while agitating for about 3 to 8 hours to convert the sulfochlorinated polyolefin-to the alkali metal sulfonate form. I

5. A method in accordance with claim l in which:

a. the alkali metal hydroxide is sodium hydroxide;

b. the slurry is exposed to $0 and Cl for a time I within the range of about 5 to about minutes at a temperature of about 0 to about 70C.

6. A method in accordance with claim 5 in which the dried chlorinated and sulfochlorinated polyolefin is treated at a temperature from. about. 60 to about C. while agitating for about 3 to about 8 hours to convert the sulfochlorinated polyolefin to the alkali metal sulfonate form.

7. A method in accordance with claim 1 in which the polyolefin comprises a propylene-ethylene copolymer.

8. A method in accordance with claim 1 in which the polyolefin is polypropylene. 

1. A METHOD FOR PREPARING CHLORINATED AND SULFONATED SOLID POLYOLEFIN OF AN ALPHA MONO-OLEFIN HAVING 3 TO 8 CARBON ATOMS IN THE MOLECULE WHICH COMPRISES: EXPOSING A STIRRED SLURRY OF SOLID CRYSTALLINE POLYOLEFIN POWDER IS CARBON TETRACHLORIDE TO A SUFFICIENT AMOUNT OF SO2 AND CL2 IN THE PRESENCE OF LIGHT FOR A SUFFICIENT LENGTH OF TIME AT A SUFFICIENT TEMPERATURE TO SULFOCHLORINATE AND CHLORINATE SAID SOLID POLYOLEFIN, DRYING THR RESULTANT SLURRY OF SULFOCHLORINATED AND CHLORINATED POLYOLEFIN, TREATING SAID DRIED SULFOCHLORINATED AND CHLORINATED POLYOLEFIN WITH A HOT AQUEOUS ALKALI METAL HYDROXIDE SOLUTION TO CONVERT SAID SULFOCHLORINATED POLYOLEFIN TO THE ALKALI METAL SULFONATE FORM, DRYING THE TREATED CHLORINATED AND ALKALI METAL SULFONATED POLYOLEFIN, AND THEN STABILIZING THE LAST DRIED POLYOLEFIN BY ADDING THERETO AT LEAST A SUFFICIENT AMOUNT OF ALKALI METAL HYDROXIDE, WITH THE PROVISO THAT THE AMOUNTS OF SO2, CL2, AQUEOUS METAL HYDROXIDE SOLUTION AND ALKALI METAL HYDROXIDE ADDED THERETO ARE SUFFICIENT TO PROVIDE SAID POLYOLEFIN WITH A MOLAR RATIO OF THE ALKALI METAL SULFONATE GROUP: ALKALI METAL HYDROXIDE WITHIN THE RANGE FROM ABOUT 1:35:1
 2. A method in accordance with claim 1 in which the alkali metal hydroxide is sodium hydroxide.
 3. A method in accordance with claim 1 in which the slurry is exposed to SO2 and Cl2 for a time within the range of about 5 to about 90 minutes at a temperature of about 0* to about 70*C.
 4. A method in accordance with claim 1 in which the dried chlorinated and sulfochlorinated polyolefin is treated at a temperature from about 60* to about 100*C. while agitating for about 3 to 8 hours to convert the sulfochlorinated polyolefin to the alkali metal sulfonate form.
 5. A method in accordance with claim 1 in which: a. the alkali metal hydroxide is sodium hydroxide; b. the slurry is exposed to SO2 and Cl2 for a time within the range of about 5 to about 90 minutes at a temperature of about 0* to about 70*C.
 6. A method in accordance with claim 5 in which the dried chlorinated and sulfochlorinated polyolefin is treated at a temperature from about 60* to about 100*C. while agitating for about 3 to about 8 hours to convert the sulfochlorinated polyolefin to the alkali metal sulfonate form.
 7. A method in accordance with claim 1 in which the polyolefin comprises a propylene-ethylene copolymer.
 8. A method in accordance with claim 1 in which the polyolefin is polypropylene. 